The present technology relates to an imaging device, an imaging apparatus, a production apparatus and method, and a semiconductor device. Specifically, the present technology relates to an imaging device, an imaging apparatus, a production apparatus and method, and a semiconductor device that are capable of appropriately and easily controlling a level of a dark signal.
In the past, there may have been caused an Optical Black (OPB) level difference which is a difference between a dark signal in an effective pixel and a dark signal in an Optical Black (OPB) pixel in an imaging device. In addition, even within an effective pixel region, the dark signal tends to vary pixel to pixel. For example, in a peripheral region of the effective pixel (a frame-shaped region), dark signal shading where the dark signal is gradually increased may be caused.
As a method of controlling or correcting such a dark signal, the following various methods have been considered.
For example, in order to control a dark signal, there has been a method of controlling the dark signal by adjusting conversion efficiencies through adjustment of a gate area of an amplifier transistor (see JP 3326940B, for example). This method may raise a concern of reduction of mutual conductance (gm) due to an increased gate area or occurrence of short channeling due to a reduced gate area, which lead to gain variability.
In addition, there is also a method of adjusting conversion efficiencies through adjustment of a wiring pattern or a diffusion layer, thereby to control the dark signal (see JP 2006-165006A, for example). However, there is a concern that changes of conversion efficiencies may lead to variations of image capturing characteristics at the time of a bright state, which may result in degraded image quality at the time of a bright state.
Moreover, there is also a method of changing sensor potentials, thereby to control the dark signal (see JP 2012-23319A, for example). In this method, a readout voltage, a saturation signal amount, and sensitivity are greatly affected, which may lead to degraded image quality at the time of a bright state.
Furthermore, there is also a method of controlling the dark signal through adjustment of an implantation layout around a pixel ground (GND) contact (see JP 2011-210837A, for example). In this method, because P+ ions are implanted at a relatively high concentration in the vicinity of an N-type region of a photodiode, occurrence of white dots or dark electric current may be concerned. In addition, because the high concentrated P+ region exists below element isolation, a depletion layer of the photodiode may be limited in a transverse direction, which may raise a concern of deterioration of saturation or sensitivity characteristics. Moreover, when donor impurities are doped at a relatively high concentration as countermeasures of such deterioration, the white points or dark electric current may become more problematic.
In addition, there is a method of reducing a degree of shading in the effective pixel by greatly enlarging a pixel extension region outside the effective pixel region in order to suppress an effect of the dark signal shading, which is typified by non-uniformity of dark electric currents in frame regions. In this method, a size of a chip may be increased by an amount of the pixel extension region, which may directly lead to decreased production yield and increased production costs.
Moreover, there is a method of correcting the OPB level difference and the dark signal shading by utilizing a pixel signal process. In this method, additional memories are necessary for the signal process, which may raise a concern of degraded image quality due to noises associated with the process.
Even in any of the methods described above, there are concerns about a degraded image quality and a complicated controlling technique. Therefore, there has been a demand for a technology that controls only the dark signal with a simplified technique, without degrading a quality of an image.
The present technology has been made in view of the above circumstances, and thus provides appropriate and easy control of a dark signal level.
According to an embodiment of the present technology, there is provided an imaging device including a semiconductor having a light-receiving portion that performs photoelectric conversion of incident light, electrically conductive wirings, and a contact group including contacts that have different sizes and connect the semiconductor and the electrically conductive wirings.
Ground contacts within the contact group may have different sizes, the ground contacts connecting a pixel well region of the semiconductor and the electrically conductive wirings at a ground potential.
A size of at least one of the ground contacts in an optical black region of the semiconductor may be different from a size of at least one of the ground contacts in an effective pixel region of the semiconductor.
The ground contacts in the optical black region may have a first size, and the ground contacts in the effective pixel region have a second size that is different from the first size.
The ground contacts in the effective pixel region may have a predetermined size, and the ground contacts in the optical black region have different sizes.
The ground contacts in an effective pixel region of the semiconductor may have different sizes.
Each of the ground contacts in the effective pixel region may have a size in accordance with an image height.
Sizes of the ground contacts in a part of the effective pixel region may be different from sizes of the ground contacts in another part of the effective pixel region.
A size of a ground contact that connects a pixel well region of the semiconductor and a corresponding one of the electrically conductive wirings at a ground potential may be different from a size of another contact excluding the ground contact, within the contact group.
The another contact may include at least one of a power source contact that connects a circuit element formed in the semiconductor and a corresponding one of the electrically conductive wirings at power source potential, a floating diffusion contact that connects a floating diffusion formed in the semiconductor and a corresponding one of the electrically conductive wirings, and a vertical signal line contact that connects a select transistor formed in the semiconductor and a corresponding one of the electrically conductive wirings.
Only the ground contact may have a predetermined size, and other contacts excluding the ground contact may have a plurality of different sizes.
Only the ground contacts may have a plurality of different sizes, and other contacts excluding the ground contact may have a predetermined size.
According to another embodiment of the present technology, there is provided an imaging apparatus including an imaging device including a semiconductor having a light-receiving portion that performs photoelectric conversion of incident light, electrically conductive wirings, and a contact group including contacts that have different sizes and connect the semiconductor and the electrically conductive wirings, and an image processing section that processes an image of a subject, the image having undergone the photoelectric conversion in the imaging device.
According to further another embodiment of the present technology, there is a production apparatus configured to produce an imaging device, the production apparatus including a setting section that sets different sizes of a plurality of contacts that connect a semiconductor and electrically conductive wirings, a semiconductor element forming section that forms elements in the semiconductor, the elements including a light-receiving portion that performs photoelectric conversion of incident light, a contact forming section that forms the contacts in accordance with setting of the setting section, and an electrically conductive wiring forming section that forms the electrically conductive wirings.
The setting section may set a size of a ground contact that connects a pixel well region of the semiconductor and a corresponding one of the electrically conductive wirings at a ground potential.
The setting section may set sizes of the ground contacts in an effective pixel region and in an optical black region in accordance with a difference between a dark signal level in the effective pixel region and a dark signal level in the optical black region.
The setting section may set sizes of the ground contacts in an effective pixel region in accordance with variations of dark signal levels due to positions of the wound contacts in the effective pixel region.
The setting section may set a size of the ground contact of an abnormal pixel in accordance with a difference between a dark signal level of the abnormal pixel and a dark signal level of a normal pixel.
According to further another embodiment of the present technology, there is a production method performed by a production apparatus that produces an imaging device, the production method including setting different sizes for contacts that connect a semiconductor and electrically conductive wirings, forming in the semiconductor, an element including a light-receiving portion that performs photoelectric conversion of incident light, forming the contacts in accordance with setting for sizes set for the contacts, and forming the electrically conductive wirings.
According to further another embodiment of the present technology, there is provided a semiconductor device including a semiconductor having a circuit element, electrically conductive wirings, and a contact group including contacts that have different sizes and connect the semiconductor and the electrically conductive wirings.
According to an embodiment of the present technology, there is provided an imaging device that includes a semiconductor having a light-receiving portion that performs photoelectric conversion of incident light, electrically conductive wirings, and a contact group including contacts that have different sizes and connect the semiconductor and the electrically conductive wirings.
According to another embodiment of the present technology, there is provided an imaging apparatus that includes an imaging device provided with a semiconductor having a light-receiving portion that performs photoelectric conversion of incident light, electrically conductive wirings, and a contact group including contacts that have different sizes and connect the semiconductor and the electrically conductive wirings, and an image processing section that processes an image of a subject, the image having undergone the photoelectric conversion in the imaging device.
According to yet another embodiment of the present technology, there is provided a production of an imaging device, which includes setting different sizes for contacts that connect a semiconductor and electrically conductive wirings, and forming a light-receiving portion that performs photoelectric conversion of incident light, in the semiconductor, the contacts in accordance with the set sizes; and the electrically conductive wirings.
According to another embodiment of the present technology, there is provided a semiconductor device that includes a semiconductor having a circuit element, electrically conductive wirings, and a contact group including contacts that have different sizes and connect the semiconductor and the electrically conductive wirings.
According to the present technology, an image of a subject can be captured. Specifically, the present technology is capable of providing an appropriate and easy control of a dark signal level.